This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The Purpose of TrialNet Natural History Study is to gain information about the pathogenesis and natural history of Diabetes Type 1;and to facilitate the recruitment and assessment of individuals who might qualify for T1D prevention trials. The TrialNet Natural History Study has been designed to clarify the genetic and immunologic factors that play a key role in the development of T1D, and the increasing characterization of the early metabolic abnormalities. In doing so, TrialNet Natural History Study will contribute to the development and implementation of TrialNet T1D prevention trials.